In order to study contrast agent flow, which is representative of blood flow through vessels in an angiography (e.g., Digitally Subtracted Angiography (DSA)) image sequence, it is useful to visualize the characteristics of flow over time at various points within an image while evaluating the need for treatment or the effectiveness of treatment. A DSA image sequence may be interpreted in known systems by determining contrast agent changes over time to indicate blood flow at particular points in an image. A known system may provide a static color image showing a single characteristic of a point in the image (e.g., time of contrast peak) but this fails to provide an indication of flow over time at different points in an image. A system according to invention principles addresses a need to provide a visual interpretation of blood flow at multiple different points in a composite image